Taperlock thread plug gages are used to check the size of internal threads to ensure the threads are within its designed tolerance limits. Taperlock thread plug gages are available with GO and/or NOGO plug members and are manufactured to Class X tolerance in 2B or 3B and to an X tolerance in Class 6H of fit for metric. Taperlock thread work plug gages are taperlock design up to 1 1/2" (38.1mm). Sizes larger than 1 1/2" are trilock design. Chip grooves are provided on all GO work Plug members in sizes #10 and larger for inch and in sizes M5 and larger for metric.

Chip grooves, also called dirt grooves, are located at the entering end of the gage. They provide a means of cleaning the dirt and other debris from the internal product thread. All gages are inspected in an environmentally controlled lab and manufactured in full conformance to ASME/ANSI B1. 2, ANSI/ASME B1.16M and/or H28 handbook gage standards. WESTport taperlock gages are manufactured to the highest end of the ANSI specifications to ensure the longest gage life possible. Taperlock thread plug gages are available in steel and chrome.